Find the (a) period, (b) phase shift (if any), and (c) range of the following function.

[tex]\[ y = \frac{7}{3} \cot \left[ \frac{1}{3} \left( x - \frac{\pi}{4} \right) \right] \][/tex]

(a) The period is [tex]\(\square\)[/tex]. (Type an exact answer in terms of [tex]\(\pi\)[/tex].)



Answer :

Let's examine the given function:
[tex]\[ y = \frac{7}{3} \cot \left[\frac{1}{3} \left(x - \frac{\pi}{4}\right)\right] \][/tex]

### (a) Period

The general form of the cotangent function is [tex]\(y = A \cot(Bx - C)\)[/tex], where [tex]\(A\)[/tex] is the amplitude, [tex]\(B\)[/tex] is the coefficient of [tex]\(x\)[/tex] that affects the period, and [tex]\(C\)[/tex] is the phase shift. The period of the cotangent function is given by:
[tex]\[ \text{Period} = \frac{\pi}{B} \][/tex]

For the given function:
[tex]\[ B = \frac{1}{3} \][/tex]

Substituting [tex]\(B\)[/tex] into the period formula:
[tex]\[ \text{Period} = \frac{\pi}{\frac{1}{3}} = 3\pi \][/tex]

### (b) Phase Shift

The phase shift of a function in the form [tex]\(y = A \cot(Bx - C)\)[/tex] is given by:
[tex]\[ \text{Phase Shift} = \frac{C}{B} \][/tex]

In the given function, [tex]\(C = \frac{\pi}{4}\)[/tex] and [tex]\(B = \frac{1}{3}\)[/tex]. Substituting these values into the formula for phase shift:
[tex]\[ \text{Phase Shift} = \frac{\frac{\pi}{4}}{\frac{1}{3}} = \frac{\pi}{4} \cdot 3 = \frac{3\pi}{4} \][/tex]

### (c) Range

The range of the cotangent function, [tex]\(\cot(x)\)[/tex], is all real numbers, since the cotangent can take any real value as [tex]\(x\)[/tex] varies over its domain (except at its asymptotes).

To summarize:

- (a) Period: [tex]\(\boxed{3 \pi}\)[/tex]
- (b) Phase Shift: [tex]\(\boxed{\frac{3 \pi}{4}}\)[/tex]
- (c) Range: [tex]\(\boxed{\text{all real numbers}}\)[/tex]

These results match the detailed analysis.